I work at a high school and the dress code for employees is the same as for the students. I try to dress better than the students do, but it's funny to see how the teachers approach it. A few of our female teachers wear nice skirts or dressy pants. Some wear jorts, or knee length shorts, some just jeans and a t-shirt.
The biggest difference is in the male teachers, some go with the shirt and tie, they say it commands respect from the students. Others dress casually. Some dress just like the students and I have a hard time finding them when I go to their classrooms, if they're not at they're desks. Of course, the PE teachers wear gym shorts, and I would too. Mr. Herring, otoh, he wears whatever he wants and commands the respect of the students. You don't mess with him